A typical problem that is encountered by motor vehicle drivers, in vehicles with manual transmissions, when they find themselves stopped on an incline and want to begin moving again, is that the vehicle begins to roll in the unwanted direction when the brake pedal is released. A conventional gearbox with an ordinary disc clutch between the gearbox and the engine does not prevent the automobile from rolling backward when starting on this upward incline as does a typical automatic transmission.
As a result, in a vehicle with a manual transmission, the hand-brake is typically used when starting on an incline. This procedure is awkward at times because the vehicle immediately moves backward once the foot on the brake pedal is lifted. When performing this procedure, the driver will normally position one foot on the clutch pedal to disengage the transmission and the other foot on the brake pedal to hold the vehicle stationary on the incline. When it is time to continue up the incline, the handbrake is engaged and the foot on the brake pedal is moved to the accelerator pedal to increase the engine speed at the same time the clutch pedal begins to return to its rest position. The handbrake is then released as the accelerator pedal is pressed. It is important to carefully coordinate the release of the hand brake with depressing the accelerator pedal and letting up of the clutch pedal in order to prevent the vehicle from initially rolling back down or stalling the engine. Also, some vehicles do not have a hand brake, and, therefore, a driver cannot perform this procedure.
Many drivers consider this to be a very difficult maneuver and therefor choose when starting on an upward incline to ride the clutch; i.e., the throttle is opened slightly over idle speed and the clutch pedal is engaged so that the clutch slips just enough to hold the vehicle stationary. This driving technique results in heavy wear on the clutch disc and, when used often, results in substantial shortening of the life of the clutch disc.
As a result, a hill holder device is desirable in a vehicle equipped with a manual transmission since this type of device prevents unwanted roll-back of a vehicle on an incline. Various types of hill holder devices have been proposed to inhibit this unwanted movement of a vehicle.
It is also desirable to have a hill hold device that will assist a driver who stops while backing up and wants to continue backing up an incline without rolling forward as the brake pedal is released.
The need arises, then, with a vehicle having a manual transmission and a conventional disc clutch, to prevent the vehicle from rolling backward when starting to move forward again on an upward incline, and to prevent the vehicle from rolling forward when starting to back up again on a downward incline, while keeping the device as simple and reliable as possible.